[Duration of action of the pyrimethamine-sulfametopyrazine combination in a Plasmodium falciparum endemic zone].

The duration of action of the drug Antemal, a combination of Pyrimethamine and Sulfametopyrazine, was eveluated in Bobo-Dioulasso, Upper Volta, West Africa, and endemic zone for Plasmodium falciparum malaria. The study was held during the season of maximum malaria transmission. 79 persons presenting with an acute attack of malaria were studied; 37 persons received a single dose of chloroquine sulfate (Nivaquine), at a dose of 15 mg./kg.; 42 persons received a single dose of Antemal at a dose of one tablet (75 mg. of Pyrimethamine and 25 mg. of Sulfametopyrazine) per 10 kg. Clinical and parasitological studies of all subjects occurred on days one, two, three, 10, 17, 24 and 31. Only one of 37 (2.7%) subjects on Antemal had a reappearance of trophozoites, occurring on day 17. Eight of 42 (19.0%) patients taking nivaquine had reappearance of trophozoites, observed between day 23 and 31. Gametocytes were observed in eight of 37 (21.6 %) persons on Antemal and in only one of 42 (2.3 %) persons on Nivaquine. These observations suggest an extended duration of protection from Antemal in semi-immune individuals. Nivaquine appeared as a potent inhibitor of gametocytogenesis.